//需求：用递归法求n的阶乘
#include <stdio.h>
int rec(int n);
int main (void){
	int n= 9;
	printf ("n!= %d",rec(n));
	return 0;
}
int rec(int n)
{

	if (n == 1)
	return 1;
	else
	return rec(n-1)*n; 
}
